Sri Lankan President Maithripala Sirisena's youngest brother has died two days after he was attacked with an ax in what authorities said was a personal dispute.

Priyantha Sirisena, 42, died in a private hospital in Colombo on Saturday after he was airlifted from his hometown of Polonnaruwa in North-Central province following the attack on Thursday, a government statement said.

The attacker has surrendered to police. The statement did not say what the dispute was about.

Priyantha Sirisena was the youngest of the president's 11 siblings. He was involved in sand mining and owned a rice milling business.

Unlike his predecessor, Mahinda Rajapaksa, whose brothers and other family members held top government positions, Sirisena has kept his family out of politics and has not given them state protection.

Sirisena was in China on a four-day official visit when the attack took place. He is expected to return Sunday night and attend his brother's funeral on Monday.